Centrifugal pumps



y 6, 1958 R. PENNINGTON 2,833,525

CENTRIFUGAL PUMPS Filed Dec. 4, 1953 2 Sheets-Sheet 1 V LZUQ'ZZZZDF May6, 1958 R. PENNINGTON CENTRIFUGAL PUMPS 2 Sheets-Sheet 2 Filed Dec. 4,1953 Z:2'w entar v United States Patent 2,833,525 CENTRIFUGAL PUMPSReginald Pennington, Manchester, England, assignor t0 Mather & PlattLimited, Manchester, England, a British company Application December 4,1953, Serial No. 396,250

Claims priority, application Great Britain December 15, 1952 4 Claims.(Cl. 257-415) a pressure suificient to overcome the pressure at the pumpend of the sleeve and to ensure a restricted flow through the sleeveclearance into the pump and to the stuifing-box packings, the sealingwater being at a temperature which the packings can withstand.

In order to obtain a supply of sealing water at the necessarytemperature and pressure, a separate pump has heretofore been required.Such a pump has to be suitable for high pressures but is required todeliver only a small volume of water and so is exceptional in design,expensive to make and troublesome to install and maintain.

The object of my invention is to simplify the means for providingsealing water when two or more centrifugal pumps are connected in seriesand when intermediate water heaters are provided.

The invention consists in a centrifugal pump installa tion for hightemperature operation comprising in series a low pressure centrifugalpump and one or more higher pressure centrifugal pumps, in which thedelivery from the low pressure pump passes through a water heater,characterised in this, that the low pressure pump has an additionalstage which gives to its delivery an additional pressure and suchdelivery is taken without heating to the annular chambers in the usualsleeves around the higher pressure pump shaft or shafts adjacent to theshaft packings to give a restricted flow through the sleeve clearancesto the said packings to protect them against excessive temperature, andto the pump suction.

Referring to the accompanying explanatory drawings:

Figure 1 is a diagrammatic view showing a centrifugal pump installationconstructed and arranged in one convenient form in accordance with thisinvention. Certain parts are shown broken away to disclose internalconstruction.

Figure 2 is a sectional view showing the last stage of the low pressurepump and the additional or booster stage of said pump. The figure showsthe upper half only of the said stages.

Figure 3 is a view of a pump comprising low, intermediate and highpressure stages, with the additional or booster stage on the lowpressure pump as in Figures 1 and 2.

Figures 1 and 2 illustrate the application of my invention to twocentrifugal pumps (a low and a high pressure pump) connected in series,with intermediate water heaters, a indicates the low pressure pump and bthe high pressure pump, The delivery from the low pressure pump 0 passesby the branch 0 and heaters d and e to the high pressure pump b by thebranch 7. The low pressure pump a has beyond its normal last stage a anadditional stageat g at its'delivery end and the delivery therefrompasses by the pipes h and i to the annular chamber j in the sleeve kwithout passing through the heaters d, e. The extra pressure created bythe additional stage of thelow pressure pump is greater than thepressure in the suction branch m of the high pressure pump, so that thestufling box packing n of the high pressurepump is subjected to the lowtemperature delivery of the additional stage g of the low pressure pump.

, The extra pressure created by the additional stage g of the low,pressurepump is relatively small but is sufficient to overcome pipefriction and the pressure at the suction end ofthe high pressure pump.

The additional stage g of the pump a also delivers water to the annularchamber 0 at the delivery end of the high pressure pump to protect thepacking p. The space q at the said delivery end of the high pressurepump is in communication by the pipe r with the suction branch 1 of thehigh pressure pump so that, as with the suction side of the pump b, thepressure in the chamber 0 is higher than in the space q, which ensuresthat the relatively cool delivery from the additional stage g dominatesat the packing p. t is a balance water pipe for the pump a and u, v aredrain pipes for water delivered at the packings n and p.

The two components s and s of the usual balance valve of the highpressure pump are normally slightly out of contact and there is a smallflow of water between said components which passes to the space q and soto the pump suction branch 1. This is known practice. The

sealing conditions at the delivery end of the pump b are thereforesimilar to those at the suction end.

It will be further appreciated that the delivery from the additionalstage g of the low pressure pump may be used to protect the packingsaround the shafts of more than one high pressure pump in a series.

The pumps may deal with liquids other than water.

In Figure 3, the complete pump comprises a low pressure pump a, anintermediate pressure pump 5 and a high pressure pump 5. There is anadditional or booster stage g on the low pressure pump. The deliveryfrom the said booster stage passes direct to the packings at the suctionand delivery ends of the intermediate pressure and high pressure pumps 5and 6 by the pipe h and its branches 1'. There is a connection 7 betweenthe delivery end 8 of the high pressure pump 6 and the high pressuresuction branch 9 and a drain connection 10 deals with any waterdelivered at the inlet end of the high pressure pump 6 past the packing11.

The intermediate pressure pump 5 is arranged similar to the highpressure pump in respect to the delivery from the booster stage g, tothe suction and delivery ends of the said pump 5 and with respect to theconnection 12 between the delivery end of the pump and its suction pipe.There is also a drain pipe 13 for any water which may pass the packingat the inlet end of the pump.

There is a drain connection 14 from the delivery ends of both the highpressure and the intermediate pressure pumps.

It will be seen that each of the pumps 5, 6 is arranged similarly to thepump b of Figure 1 with respect to the I delivery from the booster stageg, and the drain connections and the balance pressure connectionsbetween the pump delivery end and its suction side.

Whatl claim is:

l. A centrifugal pump installation for high temperature operationcomprising in series a low pressure centrifugal pump and a higherpressure centrifugal pump, a water heater, means passing the deliveryfrom the low Patented May 6, 1958 pressure "pump through the heater tothe higher pressure pump, an additional booster stage "on the lowpressure pump taking suction from the low pressure pump casing at apoint under a higher pressure than the suction of said'low pressure pumpto give an additional pressure to part only of thelow pressure pumpdelivery, shaft packings at the inlet and delivery ends of the highpressure pump, means passing the booster stage delivery without heatingto the said shaft packings to give a restricted flow through saidpackings to protect them against excessive temperatures 2. A centrifugalpump installation as claimed in claim 1 in which there are a pluralityof high pressure pumps in series, and means passing the booster stagedelivery without heating to the shaft paekings at the inlet and deliveryends of each high pressure pump.

3. A centrifugal pump installation as claimed in claim 1, inwhich meanslead the flow from'the shaft packing at the delivery end of a pump tothe suction inlet of such pump. I

4. A centrifugal pump installation as claimed in claim 3, in which adrain leads the fiow away from the shaft T packing at the suction end ofa pump.

References Cited in the file of this patent V UNITED STATES PATENTS1,590,456 Vail et a1 June 29, 1929 1.73.7,870 Telfer Dec. 3, 19291,901,154 Durdin Mar. 14, 1933 1,910,811 Peterson May23, 1933 2,347,751Reeves et al. May 2, 1944 2679,83] Henkel June 1, 1954 FOREIGN PATENTS461,860 Great Britain Feb. 25, 1937 558,278

Germany Aug. 25, 1932

